The invention concerns a process in accordance with a process for monitoring the residual charge and the capacity of a load-carrying battery system with a limiting voltage level and a minimum current.
Battery monitoring systems that determine the state of charge of the battery in the current-free condition of the battery are well-known. Systems of this type utilise the largely linear dependency of the open-circuit voltage on the acid density of the electrolyte. This acid density changes in proportion to the amount of charge that has already been drawn from the battery. These systems can determine the charging condition of the battery when the battery has been current-free for a number of hours and the internal diffusion processes have calmed down.
Furthermore, it is known from the dissertation on a process to estimate the internal values of starter batteries by Steffens,W. ("Verfahren zur Schatzung der Inneren GroBcn von Starterbatterien"), RWTIH Aachen 1987, how to estimate the values of battery condition from examining a model. These values of battery condition also cover the open-circuit voltage of the battery. Although this model operates in the current carrying condition of the battery, no information is available on the remaining energy content of the battery. Also, the formation of the model is extremely complex and in practice, therefore, it has not won recognition.